Insulating board



May 26, 1936. p w CQDWISE 2,041,696

INSULATING BOARD Filed March 8, 1930 Wm; M [24m Patented May 26, 1936 UNITED STATES 2,041,696 i msunarmonom i r 1 Philip W. Codwisc, Kenmore, N. Y., assignor to i t 'Certain-Teed Products Corporation, NewYorh; N. Y.,- a corporation of Maryland Application Marcli s, 1930, serial No. 434,390

1': Claims. (ol. 154- 44) This invention relates to insulating construction boards and has for an object production of a fiber board, monolithic or laminated, composed in part of mineral ingredients which are used as a substitute for "a certain proportionof cellulose materials heretofore found desirable as bulkihg agents in the manufacture of such composition boards.

An object of this invention is to provide an insulating board which is strong, rigid, resistant to fire, heat, cold and sound and afiected to a degree by changes in temperature and humidity.

"A further object of the invention is to provide a construction board, composed in part of mineral ingredients, which is adapted as a base for the application of plaster or stucco. t

A still further object is to provide a construction board possessing-the above advantages which is inexpensive of commercial production and easy of manufacture. 4 I

Kieselguhr or diatomaceous earth, is universally recognized as one of the best insulating substances known. Its incorporation therefore, in construction material designed to afford insulating value, is highly desirable. The substance is one of the lightest mineral substances known and is the fossilized remains of minute vegetable organisms which have been formed in such away as to retain innumerable air cells of exceedingly small size throughout them. A product incorporating this material thus contains a ufacture of insulating board or. fiber wallboard which is to be usedas construction' material.

Other objects and advantages of the present invention will becomegclear. when reference "is had to the accompanying specification and drawing which illustrate one mode of practicing it.

- The invention is-not limited in its application to the manufacture of a laminated board as hereinafter described but may as well ,..be utilized in the manufacture of any other kind of insulating board or fiber wallboard.

Figure 1 is a diagrammatic representation of one of the layers out of which the board, in the instance typified, is built, the plies of that layer r. being separated in the drawing to show-the construction thereof and their relation to each other;

Figure 2 is a perspective viewof a fragment of the complete board.

The complete board as illustrated in Figure 2 comprises separate layers, preferably five, cemented' together with asuitable adhesive. This adhesive may be a mixture of sodium silicate and finely divided mineral matter, a clear solution of sodium silicate or a vegetable glue laminating compound in which clay has been incorporated,

such as thin boiling starch. The board illustrated is about i thick. The five or more layers are identically constructed and'each of them as shown in Figure 1 preferably consists of six plies felted together during the process of manufa'c-' ture. The four outermost plies of each layer I, 2, 3 and 4 are composed of approximately 75% ,of ground wood screenings and of diatomaceous earth (kieselguhr), both by dry weight. It

isadvantageous to use diatomaceous earth of such a grade-that most of it will pass through a two hundred: mesh screen. The top plies 3 and 4 and bottom pliesl and 2 are herein referred to as the top and bottom liners. 'Each liner is i made on one cylinder of a six cylinder board ma-' chine and isapproximately .015 in thickness so 25 that if constructed in accordance with this invention-the combined .outerzgplies are approximately .030" thicken eachside. "These lihers are adhered to the inner plies to form the com-' pleted layer, all the layers being combined or felt ed'together in a continuous operation.

The two inner plies or fillers 5 and 6of each layer are composed of about 21% diatomaceous earth, 23% ground wood screenings, 4773-01? a' finestock of ground wood and 9%. mixed paper stock, all by. dry weight These fillers are preferably made to caliper .010" thick on each cylinder. If desired a quantity of asbestos fiber may i be used in the filler. layers and substitutedfor a part of the ground wood and mixed-paper above mentioned. I have found that a satisfactory filler formula is 25% asbestos fiber, 20% :diatomaceous earth, 30% finely ground wood and 25% ground wood screenings. Also it is possible to" use a combinationof diatomaceous iearth and wood fiour in place ,ofthe diatomaceousearth itself. i

The equipmentused inmaking the boardspecifically embodied inthe descriptionherein is in general the same as that usedinthe manufacture of built up fiber wallboard with the exception that the feedpassages in the board machine must be re-designed to produce a straight line flow-into,

could collect and where the diatomaceous earth could separate from the fiber. This prevents stock from accumulating at the water line and enables the weight and thickness of the sheets to be properly controlled and insures that the diatomaceous earth' remains uniformly mixed with the fibre so that in the finished product the felted fibers are thus able to act as a sustaining structure supporting the diatomaceous earth.

The above mentioned equipment includes pressing rolls which press the material as it leaves the cylinder board machine. In the pressing operation performed on each ply as it is run from the machine, the standard equipment, comprising six primary presses and three large presses, may

be utilized. I have found however, that by using the materials in proportions thereof herein disclosed it is advantageous to use only the alternate primary presses with very little pressure being applied on the first one, slightly more on the second and considerable pressure onthe third, the other three primary presses being Jacked up out of the way. It is also advisable to omit the use of some of the large presses and to use very little pressure on the ones retained. This procedure results in a ply sheet calipering close to .080" and weighing approximately 2.40 ounces per square foot. Five of these sheets may' be conveniently laminated to form the finished product.

It is understood that a coarse stock consisting largely ofground wood screenings is used in the outer plies or liners, while finer stock containing finely ground wood and mixed papers is used for the inner plies or fillers. The'proportions mentioned are illustrative of one form only of making the laminated board and I do not wish to be understood as limiting the application of the invention to the particular percentages given for this purpose. In the manufacture of a monolithic board the proportions of material used may be substantially the same as that of the combined liner and filler furnishes above described. A satisfactory formula for a monolithic board is 55% ground wood screenings, 20% mixed paper and 25% diatomaceous earth; a small percentage of wood fiour may at times be combined in formula to advantage.

For sizing the material going into the manufac-- ture of my new construction board I have found that a mixture .of 3% rosin-size, 1% wax beater sizing and 4% papermakers alum, all figured as dry weight percentages, is effective in producing a hard finish and one which is resistant to the attack of certain laminating compounds such as silicateof soda. The beater sizing and rosin size are set by the alum. By paraflln wax beater sizing I refer to a sizing material which is added to the beating engines or Hollanderbeaters in the same way that ordinary size is added, and which is composed largely of a yellow scale parailin wax or the like. The sizing is preferably done by mixing it with the ingredients'in the beater with the furnish. a

I found that by the-use ofv the above described proportion of diatomaceous earth in furnish used in the production of constructitjn board, a stock of very little tendency to' cont'ract or expand is obtained. A large proportion of inert material is present in the completed board, which material will tend not to expand or contract when taking on or giving ofl moisture. By actual test it has been found that the expansion, under the same conditions, of a laminated construction board made as herein described, is approximately which kieselguhr has not been incorporated, and

that a lesser moisture absorption is distinctly apparent. The above mentioned test was conducted by measuring the expansion and water absorption from a bone dry board exposed to relative humidity and 75 degrees Fahrenheit for a period of ninety-six hours. By utilizing the principle herein described it is possible to obtain a product of little increase in weight over that obtained through the use of sawdust, wood flour 'or other fibrous bulking materials heretofore used. 'This advantage is obtained by virtue of the extraordinary bulking properties of the mineral material used when utilized in accordance with this invention.

The incorporation of diatomaceous earth as a component part of wallboard or fiber wallboard to provide the insulating quality and the'other advantages and useful results obtained therefrom 'as herein described is believed to be new in the construction field. The product is uniform in appearance and in thiclmess and weighs in the neighborhood of 970 pounds per thousand square feet, whereas fiberboard, which is generally less than one half the thickness of the new board, weighs approximately 580 pounds per thousand square feet, and fiber insulating board, as now made by means of wood fiber ingredients alone. weighs approximately 970 pounds per thousand square feet for a board of approximately the. same thickness. Not only does the new product compare favorably in weight with similar products already in commercial production. but the new board possesses other advantages thereover, such as its being fire resistant, heat, cold and sound insulating and vermin proof. A product has thus been created which possesses distinct advantages over similar products known in the art.

Obviously the various features of the invention need not necessarily be used conjointly but they may be effectively utilized in various different combinations and subcombinations.

Having thus described my invention I claim:

1. An insulating wallboard comprising a plurality of layers of a material composed of a plurality'of plies containing ground wood and diatomaceous earth. the plies being feltedtogether,

andthe inner layers. containing mixed paper stock.

2. An insulating wallboard comprising a plurality of layers of a material composed of a plurality of plies containing ground wood and diatomaceous earth, the plies being felted together, and the inner layerscontalning asbestos fibre.

3. An insulating board comprising a mixture of ground wood screenings and mixed paper stock felted without a binder to form the bulk of the mass of the board as a self-sustaining structure and diatomaceous earth distributed throughout said mass.

4. An'insulating wall board comprising a plurality of layers, at least some of said layers containing a plurality of plies of felted cellulose ground wood and. waste fibers being in amount sufficient and being so felted together asto form the bulk of the mass of the material as a rigid half as great assimilar laminated boardsin self-sustaining structure, said non-fibrous, inert fibers.

6. A composite material comprising cellulose fibers, waste cellulose fibers, and diatomaceous earth, said cellulose fibers being felted together i and the diatomaceous earthbeing distributed through and being carried by the mass of felted fibers, the proportions of the amounts of said fibers and of said diatomaceous earth being such that the diatomaceous earth provides a substantial insulating quality in the composite material while being so limited in amount with respect to the amount of the cellulose fibers that said mass of felted fibers forms a rigid self-sustaining structure. 7

7. A laminated wall board comprising a plurality of layers of fibrous cellulose material at least some of said layers comprising ground wood fibers, waste cellulose fibers, and diatomaceous earth, said ground wood and waste cellulose fibers being felted together and the diatomaceous earth being distributed through and being carrled by the mass of said felted fibers.

8. A composite material comprising ground wood fiber, waste stock of cellulose fiber, and diatomaceous earth, the ground wood and waste cellulose fiber being felted together and the diatomaceous earth being distributed through the mass of the felted fibers.

9. A composite material comprising ground wood fibers, ground wood screenings, and diatomaceous earth, the ground wood fiber and the ground wood screenings being felted together and the diatomaceous earth being distributed through and being carried by the mass of the felted fibers.

10. "A laminated wall board comprising a plurality of layers, at least some of said layers containing a plurality of plies of felted cellulose fibers, at least some of said plies containing ground wood fibers, at least some of said plies containing waste cellulose fibers, at least some of said plies of felted fibers having distributed therethrough diatomaceous earth in amount to provide in the wall board a substantial insulating quality while being carried by saidfelted ply.

11. An insulating wall board comprising cellulose fibers and cellulose pulp screenings felted without a binder to form the bulk of .the mass the board as a rigid self-sustaining structure,

each composed largely, of

anddiatomaceous earth distributed throughout said mass in amount suillcient to provide a sub.- stantial insulating quality in the board but insufiicient to prevent the board from maintaining its rigid self-sustaining structure as a wall board. 5 12. An insulating wall board comprising ground wood fibers and waste stock of cellulose fibers felted together without a bindingmaterial and in amount suificient to form the bulk of the mass of the board as a rigid self-sustaining structure, and diatomaceous earth distributed throughout said mass in amount insufilcient to prevent said board maintaining said rigid self-sustaining structure but in amount to provide a substantial insulating quality.

13. A composite material comprising ground wood fiber, ground wood screeningawaste paper stock, and diatomaceous earth, the fibrous materials being felted together and the diatomaceous earth being distributed through the mass of the felted fibers.

14. A composite material comprising ground wood screenings, waste paper stock, and diatomaceous earth, the fibrous materials being felted together and the diatomaceous earth being distributecl through the mass of the felted fibers.

.15. A composite material comprising ground wood fiber, waste paper stock, and diatomaceous earth, the, fibrous materials being felted together and the diatomaceous earth being distributed through the mass of the felted fibers.

16. A'fibrous sheet used as a layer in a laminated wall board comprising a plurality of plies fibrous cellulose material, and diatomaceous earth substantially of a fineness to pass through a 200 'mesh screen and in amounts in relation to the fibrous cellulose material of the degree of 20 to 25% based on the sum of the weights of the fibrous material and the diatomaceous earth, said cellulose fibers be- 0 ing felted together and the diatomaceous earth being substantially uniformly distributed through and being carried by a mass of said felted fiber in each ply.

17. A composite material in sheet form as defined in claim 6 in which the proportion of the diatomaceous earth is of the degree of 20 to 25% based on the sum of the weights of the fibrous materials and the diatomaceous earth, the screen size of the diatomaceous earth being sufliciently small to produce in the sheet material the desired resistance to humidity, sound, heat and fire.

' PHILIP w. conwrsn. 

